An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

Notorious artist squat renovated into legal studios.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

A hands-off space for graffiti artists to hone and display their skills.

The "beautiful" equation predicting the movement of all electromagnetic particles is engraved in front of Newton's tomb.

The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

The maritime museum that boasts the largest nautical library in the western hemisphere.

Inspired by a foil-wrapped potato, (seriously) the Markel Building has been deemed one of the 10 ugliest buildings in the world.

Heron, whitewater rapids, and urban industrialism all add to the beauty of this concrete nature walk.

This 29-ton granite ball spins around at the slightest touch thanks to a scientific phenomenon.

The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

One man's attempt to create an artistic wonder on a run-down block in Detroit.

These enduring murals depicting a distinctly Marxist tribute to capitalism could not even be defeated by McCarthyism.

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

The Beaux-Arts aquarium boasts a vast collection of saltwater and freshwater fish on an island in the Detroit River.